Michael Braus studies a major property of soil called soil pH, which has emerged as a key predictor of soil microbial community composition. This ubiquitous measurement is also central to chemical assessments of soil health and the modeling of any soil’s biogeochemical processes. The traditional or standard method for determining soil pH prepares a one-to-one water-to-soil slurry, in which a glass pH electrode is immersed. Despite the standardization of this method, Michael is able to clarify this for soil ecologists interested in the conditions organisms actually experience in their lives. Among bacteria, this external acidity may directly govern the production of ATP, rotation of flagellar motors, membrane transport systems, and energy expenditures to maintain a neutral internal condition. Water content of a soil slurry is far from a normal soil water content, and therefore the standard method introduces significant artifacts in our estimates of soil pH. In situ soil pH, alternatively, requires a suite of novel methods of measurement of acidity of soil solution at normal water content. He has measured soil pH while simulating in situ conditions of unsaturated soil water content and an atmosphere of 2-3% CO2 for a range of soils of Wisconsin to compare to standard soil pH values. In situ soil pH values may be an improved predictor of soil microbial community composition than standard soil pH values, yet in situ soil pH cannot be easily derived from standard soil pH values. Mr. Braus proposes an alternative metric for acidity in soil (and all materials) called “Grotthuss-Mitchell proticity” to replace pH (the acidity function proposed in 1909 by Sørensen), which he has determined is poorly applicable to soil.